U.S. patent application number 11/931062 was filed with the patent office on 2008-06-12 for apparatus for managing power in passive tag and method thereof.
This patent application is currently assigned to ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. Invention is credited to Ji- Hoon BAE, Jong- Suk CHAE, Gil- Young CHOI, Alex JANEK, Jae- Young JUNG, Hee- Sook MO, Josef PRIESHUB-PFLURGL, Cheol- Sig PYO, Andreas SCHUHA, Hae- Won SON, Junho YEO.
Application Number | 20080136643 11/931062 |
Document ID | / |
Family ID | 39497331 |
Filed Date | 2008-06-12 |
United States Patent
Application |
20080136643 |
Kind Code |
A1 |
YEO; Junho ; et al. |
June 12, 2008 |
APPARATUS FOR MANAGING POWER IN PASSIVE TAG AND METHOD THEREOF
Abstract
According to the present invention, the apparatus receives a
radio frequency (RF) signal transmitted from the Radio Frequency
Identification (RFID) reader, measures the strength of the received
RF signal, and controls the power supplied from the power supply
unit included in the tag or the power excited by the RF signal to
be supplied to the tag according to whether the power excited by
the received RF signal exceeds a level necessary to operate the tag
based on the measured strength of the RF signal. Thus, efficiency
of power consumption of the tag and the RFID transmission/reception
system can be maximized and the amount of data is reduced to the
extent that the set of commands is not needed, thereby simplifying
a data process.
Inventors: |
YEO; Junho; (Daegu-City,
KR) ; PRIESHUB-PFLURGL; Josef; (Klagenfurt, AT)
; JANEK; Alex; (Klagenfurt, AT) ; SCHUHA;
Andreas; (Klagenfurt, AT) ; SON; Hae- Won;
(Daejeon-city, KR) ; JUNG; Jae- Young;
(Daejeong-city, KR) ; MO; Hee- Sook;
(Daejeon-city, KR) ; BAE; Ji- Hoon; (Daejeon-city,
KR) ; CHOI; Gil- Young; (Daejeon-city, KR) ;
PYO; Cheol- Sig; (Daejeon-city, KR) ; CHAE; Jong-
Suk; (Daejeon-city, KR) |
Correspondence
Address: |
CANTOR COLBURN, LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
ELECTRONICS AND TELECOMMUNICATIONS
RESEARCH INSTITUTE
Daejeon-city
KR
|
Family ID: |
39497331 |
Appl. No.: |
11/931062 |
Filed: |
October 31, 2007 |
Current U.S.
Class: |
340/572.2 |
Current CPC
Class: |
G06K 19/0707 20130101;
G06K 19/0723 20130101; G06K 19/0712 20130101 |
Class at
Publication: |
340/572.2 |
International
Class: |
G08B 13/14 20060101
G08B013/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 2006 |
KR |
10-2006-0125031 |
Claims
1. An apparatus for managing power in a passive tag which
communicates with a Radio Frequency Identification (RFID) reader
according to an RF signal transmitted from the RFID reader, the
apparatus comprising: a power supply unit which supplies an
operating power of the tag according to a predetermined control; a
power reception unit which receives the RF signal transmitted from
the RFID reader; a power management unit which measures a strength
of the RF signal received from the power reception unit and
supplies a power excited by the RF signal or the operating power of
the tag from the power supply unit according to control based on a
result of the measuring; and a control unit which controls the
power management unit so that the power excited by the RF signal
according to the strength of the RF signal measured by the power
management unit or the power from the power supply unit is supplied
to the tag.
2. The apparatus of claim 1, wherein the power management unit
measures a voltage level of the received RF signal so as to measure
the strength of the RF signal.
3. The apparatus of claim 1, wherein when it is determined that the
power to be excited by the RF signal based on the strength of the
RF signal exceeds a fixed level necessary to operate the tag, the
control unit controls the power excited by the RF signal only to be
supplied to the tag.
4. The apparatus of claim 1, wherein in the RF signal received from
the RFID reader, a first received command is used to measure the
strength of the RF signal and a second received command is used to
communicate with the RFID reader.
5. The apparatus of claim 1, wherein the first received command of
the RF signal received from the RFID reader is used to measure the
strength of the RF signal and to communicate with the RFID
reader.
6. The apparatus of claim 1, wherein in the RF signal received from
the RFID reader, an unmodulated carrier is used to measure the
strength of the RF signal and the first received command is used to
communicate with the RFID reader.
7. The apparatus of claim 1, wherein in the RF signal received from
the RFID reader, a non-communication protocol carrier is used to
measure the strength of the RF signal and the first received
command is used to communicate with the RFID reader.
8. The apparatus of claim 1, wherein the tag is operated in order
to communicate with the RFID reader.
9. A method of managing power in a passive tag which communicates
with an RFID reader according to an RF signal transmitted from the
RFID reader, the method comprising: receiving the RF signal
transmitted from the RFID reader; measuring a strength of the
received RF signal; and controlling a power supplied from a power
supply unit included in the tag or a power excited by the RF signal
to be supplied to the tag according to whether the power excited by
the received RF signal exceeds a level necessary to operate the tag
based on the measured strength of the RF signal.
10. The method of claim 9, wherein in measuring the strength of the
received RF signal, a voltage level of the RF signal is measured so
as to measure the strength of the RF signal.
11. The method of claim 9, wherein in controlling the power excited
by the RF signal to be supplied to the tag, when it is determined
that the power to be excited by the RF signal based on the strength
of the RF signal exceeds a fixed level necessary to operate the
tag, only the power excited by the RF signal is controlled to be
supplied to the tag.
12. The method of claim 9, wherein in the RF signal received from
the RFID reader, a first received command is used to measure the
strength of the RF signal and a second received command is used to
communicate with the RFID reader.
13. The method of claim 9, wherein the first received command of
the RF signal received from the RFID reader is used to measure the
strength of the RF signal and to communicate with the RFID
reader.
14. The method of claim 9, wherein in the RF signal received from
the RFID reader, an unmodulated carrier is used to measure the
strength of the RF signal and the first received command is used to
communicate with the RFID reader.
15. The method of claim 9, wherein in the RF signal received from
the RFID reader, a non-communication protocol carrier is used to
measure the strength of the RF signal and the first received
command is used to communicate with the RFID reader.
16. The method of claim 9, wherein the tag is operated in order to
communicate with the RFID reader.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2006-0125031, filed on Dec. 8, 2006, in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a battery or power that is
managed in a passive tag, and more particularly, to power
management which maximizes an efficiency of power consumption of a
tag and a Radio Frequency Identification (RFID)
transmission/reception system by consuming power of the battery
included therein when the strength of the RF power transmitted from
a reader is determined and the amount of the RF power is not
sufficient to operate the tag.
[0004] The present invention is derived from the research performed
as a part of the information technology (IT) new growth power core
technology development business, which was hosted by the Ministry
of Information and Communications Republic of Korea (MIC) and the
Institute for Information Technology Advancement (IITA) [Task
management No.: 2005-S-106-02, entitled "Development of Sensor Tag
and Sensor Node Technologies for RFID/USN"].
[0005] 2. Description of the Related Art
[0006] A Radio Frequency Identification (RFID) is a process or chip
which puts information about processes of producing, distributing,
storing, and selling products into a tag attached to the products,
has its own antenna, makes a RFID reader read the information, and
connects with an artificial satellite or uses mobile communication
in order to access an information system.
[0007] Meanwhile, a RFID system includes a tag and a reader,
wherein the tag stores information and exchanges data according to
a protocol and the reader communicates with the tag.
[0008] The RFID tag can be classified into an active type and a
passive type, wherein the active type needs a power source and uses
a direct power supply, and the passive type is operated by an
electromagnetic field of the reader without power being supplied
directly from inside or outside of the RFID tag. By using the
active type, required power for the reader is reduced and an
identification distance may be far from the reader. However, since
a power supply device is needed, the operation time is limited and
the cost of the active type is more expensive than the passive
type. On the other hand, the passive type is lighter than the
active type, the cost of the passive type is less than the active
type, and the passive type can be used semi-permanently. However,
when the passive type is used, an identification distance is short
and more power is consumed by the reader, compared to when the
active type is used.
[0009] In addition, a battery powered passive tag, which combines
the active type and the passive type, has been suggested.
[0010] However, according to the conventional battery powered
passive tag, whether to operate the battery included therein is
determined by the reader. Accordingly, the reader should transmit
data including a separate set of commands indicating whether to
operate the battery to the tag and the tag also should process the
separate set of commands. Therefore, the reader and the tag consume
more power in order to process the set of commands, thus causing
various problems such as reduction of identification distance,
shortening of the life of the battery included in the tag, and
complication of transmitted/sent data.
SUMMARY OF THE INVENTION
[0011] The present invention provides an apparatus for managing
power in a passive tag and a method thereof, in which power of a
battery included therein is consumed when an amount of the power
transmitted from a reader is not sufficient to operate a tag.
[0012] According to an aspect of the present invention, there is
provided an apparatus for managing power in a passive tag which
communicates with a Radio Frequency Identification (RFID) reader
according to an RF signal transmitted from the RFID reader, the
apparatus including: a power supply unit which supplies an
operating power of the tag according to a predetermined control; a
power reception unit which receives the RF signal transmitted from
the RFID reader; a power management unit which measures a strength
of the RF signal received from the power reception unit and
supplies a power excited by the RF signal or the operating power of
the tag from the power supply unit according to control based on a
result of the measuring; and a control unit which controls the
power management unit so that the power excited by the RF signal
according to the strength of the RF signal measured by the power
management unit or the power from the power supply unit is supplied
to the tag.
[0013] The power management unit may measure a voltage level of the
received RF signal so as to measure the strength of the RF signal.
When it is determined that the power to be excited by the RF signal
based on the strength of the RF signal exceeds a fixed level
necessary to operate the tag, the control unit may control the
power excited by the RF signal only to be supplied to the tag.
[0014] According to another aspect of the present invention, there
is provided method of managing power in a passive tag which
communicates with an RFID reader according to an RF signal
transmitted from the RFID reader, the method including: receiving
the RF signal transmitted from the RFID reader; measuring a
strength of the received RF signal; and controlling a power
supplied from a power supply unit included in the tag or a power
excited by the RF signal to be supplied to the tag according to
whether the power excited by the received RF signal exceeds a level
necessary to operate the tag based on the measured strength of the
RF signal.
[0015] In measuring the strength of the received RF signal, a
voltage level of the RF signal may be measured so as to measure the
strength of the RF signal. In controlling the power excited by the
RF signal to be supplied to the tag, when it is determined that the
power to be excited by the RF signal based on the strength of the
RF signal exceeds a fixed level necessary to operate the tag, only
the power excited by the RF signal may be controlled to be supplied
to the tag.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
[0017] FIG. 1 is a block diagram of an apparatus for managing power
in a passive tag according to an embodiment of the present
invention; and
[0018] FIG. 2 is a block diagram of a tag including an apparatus
for managing power in a passive tag according to an embodiment of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Hereinafter, the present invention will be described more
fully with reference to the accompanying drawings, in which
exemplary embodiments of the invention are shown.
[0020] FIG. 1 is a block diagram of an apparatus for managing power
in a passive tag according to an embodiment of the present
invention.
[0021] The apparatus manages power in the tag which communicates
with a Radio Frequency Identification (RFID) reader according to an
RF signal transmitted from the RFID reader. The apparatus includes
a power supply unit 100, a power reception unit 110, a power
management unit 120, and a control unit 130. The power supply unit
100 supplies the operating power of the tag according to a
predetermined control strategy. The power reception unit 110
receives the RF signal transmitted from the RFID reader. The power
management unit 120 measures the strength of the RF signal received
from the power reception unit 110 and supplies the power excited by
the RF signal or the power to operate the tag from the power supply
unit 100 according to the control of the measurement result. The
control unit 130 controls the power management unit 120 so that the
power excited by the RF signal according to the strength of the RF
signal measured by the power management unit 120 or the power from
the power supply unit 100 is supplied to the tag.
[0022] In FIG. 1, a memory included in the tag, a sensor, a
modulator and a demodulator are not illustrated. Also, a specific
part of FIG. 1 can be substantially embodied to be included in a
device such as an application specific integrated circuit (ASIC)
and thus the elements of the apparatus according to the present
invention are divided into TAG and ASIC in FIG. 2.
[0023] The apparatus receives the RF signal transmitted from the
RFID reader, measures the strength of the received RF signal, and
controls the power supplied from the power supply unit 100 included
in the tag or the power excited by the RF signal to be supplied to
the tag according to whether the power excited by the received RF
signal exceeds a level necessary to operate the tag based on the
measured strength of the RF signal. Such processes will be
described below.
[0024] FIG. 2 is a block diagram of a tag including an apparatus
for managing power in a passive tag according to an embodiment of
the present invention.
[0025] The tag of FIG. 2 includes an antenna 210, a voltage
multiplying unit 212, a demodulator 214, a modulator 216, a power
management unit 220, a main power unit (battery) 200, a
supplementary power unit (Sustain Capacitor) 202, a volatile memory
(VM) 240, a non-volatile memory (NVM) 242, a sensor 244, and a
control unit (central logic) 230.
[0026] Comparing FIG. 1 and FIG. 2, the power supply unit 100 of
FIG. 1 corresponds to the main power unit (battery) 200 and the
supplementary power unit (sustain capacitor) 202 of FIG. 2, the
power reception unit 110 of FIG. 1 corresponds to the antenna 210
and the voltage multiplying unit 212 of FIG. 2, the power
management unit 120 of FIG. 1 corresponds to the power management
unit 220 of FIG. 2, and the control unit 130 of FIG. 1 corresponds
to the control unit (central logic) 230 of FIG. 2.
[0027] The voltage multiplying unit 212 generates a DC voltage from
the analog RF signal received through the antenna 210 and outputs
the DC voltage to the power management unit 220.
[0028] The demodulator 214 demodulates data received through the
antenna 210 and outputs the demodulated data to the control unit
230. The modulator 216 modulates data input from the control unit
230 and transmits the modulated data to the RFID reader through the
antenna 210.
[0029] The power management unit 220 measures the strength of the
power of the RF signal input from the voltage multiplying unit 212
and outputs `strength information` of the corresponding signal to
the control unit 230. Also, the power management unit 220 supplies
the RF power excited by the RF signal transmitted from the RFID
reader or the power of the main power unit 200 to elements that
need a power supply from the tag, that is, the VM 240, the NVM 242,
the sensor 244, the supplementary power unit, and the control unit
230, based on the signal input from the control unit 230 in
correspondence to the strength information.
[0030] Moreover, the power management unit 220 measures a remaining
amount of power of the main power unit 200 and corresponding
`remaining information` is output to the control unit 230.
[0031] When it is determined from the strength information input
from the power management unit 220 that the RF power is sufficient
as the power used to operate the tag, the control unit 230 controls
the power management unit 220 so as to accomplish the power supply
according to a predetermined method, for example, a backscatter
coupling method. In addition, when the RF power is not sufficient,
the control unit 230 controls the power management unit 220 so that
the power stored in the main power unit 200 is used.
[0032] In addition, when it is determined from the remaining
information input from the power management unit 220 that
insufficient power remains in the battery which is the main power
unit 240, the control unit 230 controls the modulator 216 so that a
signal indicating that no power remains in the main power unit 220
is transmitted to the RFID reader by using the RF power transmitted
from the reader.
[0033] In addition to this, in the apparatus for managing power
according to the present invention, the RF signal received from the
RFID reader can be used in various ways as described below.
[0034] In other words, in the apparatus for managing power, a first
received command of the RF signal received from the RFID reader can
be used to measure the strength of the RF signal and a second
received command of the RF signal can be used to communicate with
the RFID reader.
[0035] Also, the first received command of the RF signal received
from the RFID reader can be used to measure the strength of the RF
signal and to communicate with the RFID reader.
[0036] In addition, an unmodulated carrier of the RF signal
received from the RFID reader can be used to measure the strength
of the RF signal and to communicate with the RFID reader.
[0037] Moreover, a non-communication protocol carrier of the RF
signal received from the RFID reader can be used to measure the
strength of the RF signal and the first received command can be
used to communicate with the RFID reader.
[0038] Such operations can be performed by controlling the power
management unit 220, the demodulator 214, and the modulator 216
with reference to techniques of the present invention.
[0039] According to the present invention, the apparatus receives
the RF signal transmitted from the RFID reader, measures the
strength of the received RF signal, and controls the power supplied
from the power supply unit included in the tag or the power excited
by the RF signal to be supplied to the tag according to whether the
power excited by the received RF signal exceeds a level necessary
to operate the tag based on the measured strength of the RF signal.
Thus, efficiency of power consumption of the tag and the RFID
transmission/reception system can be maximized and the amount of
data is reduced to the extent that the set of commands is not
needed, thereby simplifying a data process.
[0040] In addition, it is obvious to one of ordinary skill in the
art that each process can be embodied in various ways with software
or hardware by using a general programming method.
[0041] While the present invention has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood by those of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope of the present invention as defined by
the following claims.
* * * * *